Answer
$\dfrac{(c+3)}{(c-3)}; c \ne 3$
Work Step by Step
Given: $\dfrac{3c+9}{3c-9}$
Need to find the common factors of the given expression.
$\dfrac{3c+9}{3c-9}=\dfrac{3(c+3)}{3(c-3)}$
$=\dfrac{(c+3)}{(c-3)}$
If we put $c=3$ then denominator becomes zero, which cannot be possible.
After simplification, we get
$=\dfrac{(c+3)}{(c-3)}; c \ne 3$
